Mapping states in binary arithmetic coder for video coding

Patent metadata

Field	Value
Publication number	US-9871537-B2
Application number	US-201213660540-A
Country	US
Kind code	B2
Filing date	Oct 25, 2012
Priority date	Oct 27, 2011
Publication date	Jan 16, 2018
Grant date	Jan 16, 2018

Abstract

This disclosure describes techniques for binary arithmetic coding in video coding, and video encoders and decoders for performing such techniques. In some examples, the techniques may support binary arithmetic coding that supports slower adaptation rates and accounts more extreme probabilities (i.e., probabilities closer to 0 and 1) while maintaining relatively small tables.

First claim

What is claimed is:

1. A method of entropy coding of video data using a binary arithmetic coding process in a video coding process, the method comprising:
determining a probability state of a symbol related to high definition (HD) video content in a binary arithmetic coding process, wherein the probability state is determined from a plurality of probability states for the HD video content, wherein a number of the plurality of probability states is greater than sixty-four (64), and wherein sixty-four (64) probability states represents a number of probability states used for video content having a resolution lower than the resolution associated with the HD video content; and
mapping an index indicating the determined probability state to one of sixty-four (64) grouped indexes,
wherein at least one grouped index of the sixty-four (64) grouped indexes represents at least two of the plurality of probability states, and wherein each of the sixty-four (64) grouped indexes identifies a range for a probability symbol in a table.

2. The method of claim 1 , wherein the number of the plurality of probability states is 128.

3. The method of claim 1 , further comprising coding the symbol based on the grouped index and the probability state.

4. The method of claim 3 , wherein coding the symbol comprises coding the symbol according to a table based on the grouped index.

5. The method of claim 3 , wherein coding the symbol comprises coding the symbol according to a mathematical operation performed on the index to generate the grouped index.

6. The method of claim 1 , wherein mapping comprises mapping the index to a grouped index according to a table.

7. The method of claim 1 , wherein mapping comprises mapping the index to the grouped index according to a mathematical operation.

8. The method of claim 7 , wherein mapping comprises mapping the index to the grouped index according to a divide-by-two operation.

9. The method of claim 1 , wherein mapping comprises mapping the index to the grouped index according to a linear mapping.

10. The method of claim 1 , wherein mapping comprises mapping the index to the grouped index according to a logarithmic mapping.

11. The method of claim 1 , wherein mapping comprises mapping the index to the grouped index according to a piecewise nonlinear mapping.

12. The method of claim 1 , wherein the plurality of probability states includes a highest probability state p 0 , and wherein successive probability states are determined by multiplying a previous probability state with a parameter α, wherein α is greater than 0.9493, and wherein p 0 is less than 0.5.

13. The method of claim 12 , wherein α is approximately 0.9689 and wherein p 0 is approximately 0.493.

14. The method of claim 3 , wherein the video coding process is a video encoding process, the method further comprising:
encoding video data to produce residual data;
transforming residual data to produce transform coefficients; and
binarizing the transform coefficients to create the symbols.

15. The method of claim 3 , wherein the video coding process is a video decoding process, wherein coding the symbol based on the grouped index and the probability state produces decoded bins, the method further comprising:
receiving the symbols;
reverse binarizing the decoded bins to produce transform coefficients;
inverse transforming the transform coefficients to produce residual data; and
decoding the residual data to produce decoded video data.

16. A non-transitory computer-readable storage medium storing instructions that, when executed, cause one or more processors of a device configured to perform entropy coding of video data using a binary arithmetic coding process in a video coding process to:
determine a probability state of a symbol related to high definition (HD) video content in a binary arithmetic coding process, wherein the probability state is determined from a plurality of probability states for the HD video content, wherein a number of the plurality of probability states is greater than sixty-four (64), and wherein sixty-four (64) probability states represents a number of probability states used for video content having a resolution lower than the resolution associated with the HD video content; and
map an index indicating the determined probability state to one of sixty-four (64) grouped indexes, wherein at least one of the grouped indexes represents at least two of the plurality of probability states, and wherein each of the sixty-four (64) grouped indexes identifies a range for a probability symbol in a table.

17. The non-transitory computer-readable storage medium of claim 16 , wherein the number of the plurality of probability states is 128.

18. The non-transitory computer-readable storage medium of claim 16 , further comprising instructions for causing the one or more processors to code the symbol based on the grouped index and the probability state.

19. The non-transitory computer-readable storage medium of claim 16 , wherein the plurality of probability states includes a highest probability state p 0 , and wherein successive probability states are determined by multiplying a previous probability state with a parameter α, wherein α is greater than 0.9493, and wherein p 0 is less than 0.5.

20. The non-transitory computer-readable storage medium of claim 19 , wherein α is approximately 0.9689 and wherein p 0 is approximately 0.493.

Assignees

• Qualcomm Inc

Inventors

• Sole Rojals Joel
• Karczewicz Marta

Classifications

• H03M7/42 Primary

  using table look-up for the coding or decoding process, e.g. using read-only memory {(H03M7/4006 takes precedence)} · CPC title

• H04N19/13

  Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC] · CPC title

• H04N19/61

  in combination with predictive coding · CPC title

• H04N19/91

  Entropy coding, e.g. variable length coding [VLC] or arithmetic coding · CPC title

• H03M7/4018

  Context adapative binary arithmetic codes [CABAC] · CPC title